In general, footwear, and more specifically, shoes, come in all shapes and sizes, and are used for a variety of different activities. For example, there are shoes for formal wear, such as men's dress shoes, and ladies' heels, and there are shoes for casual wear, such as sneakers and the like.
Additionally, there are shoes that are specifically made for a particular activity, such as a sport. There are many different types of sport shoes, including tennis shoes, basketball shoes, rock climbing shoes, and some of these types of athletic shoes are used on grass, and thus include cleats, such as football, baseball, soccer, and golf shoes.
Traditionally, shoes are made up of three components, an upper, which is the top and usually largest part of the shoe. The upper is the part of the shoe that the user would insert their foot into and possibly lace it closed. The next component would be the midsole, which is located directly beneath the upper, and usually contains some sort of shock absorbing and/or supporting material. The midsole also serve as the mounting surface for the outsole, the third component of a typical shoe. The outsole is the part of the shoe that comes into direct contact with the ground, and is usually made of a tough material. Some outsoles include cleats to allow a user to gain traction in soft surfaces, such as grass and mud.
Depending on the purpose for which a shoe will be used, the geometry and makeup of each component of the shoe will vary. For example, a basketball shoe typically has a high top upper, to allow for ankle support, and flat outsole to allow for maximum traction on a hard and flat surface.
Thus far, the various components of a shoe, namely the upper, midsole, and outsole, have been permanently attached together by means such as stitching, glue, tape, staples, and the like. Such a fabrication has limited each shoe's usability to a single purpose, and has thereby forced consumers to purchase several different shoes, each for its own purpose, which can be impractical and costly. Although there have been some forms of replaceable soles, the surface of such soles have been limited to one specific geometry and material make up, and thus have limited customization capabilities.
Also, traditional soles, including replaceable soles, have been formed of a single piece, which forces a user to have to replace the entire sole when only a part of it has worn out. This is impractical and wasteful, since it is very common for certain parts of a sole to wear out more than others throughout the life of a sole.